<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var str = "hello"
        var age = 18;
        console.log("world"+str);
        // 字符串模板，可以在字符串中插入变量${}
        var sum = `world${str}`;
        console.log(sum)
    </script>
</body>
</html>